Engine starts right up but dies with first few minutes

[Joe Warren 75]

I have a Kohler 301K engine with a Carter carburetor. The engine has always performed very well, but recently has been stalling out after running only a short time. I initially thought it was being starved for fuel. I cleaned and rebuilt the carburetor, replaced fuel filter, and replaced the fuel tank which had some corrosion. I even replaced the Carter carburetor with a new Walbro but I am still having the same issue. I am now suspecting the problem is electrical. What is the likely culprit?  Coil? Condenser? Spark plug?  Points? 

Other?

Appreciate your input, 

Joe

[Pullstart 59,679]

Try cracking the gas cap loose and report back with any changes.  It sounds like a plugged vent.  

[daveoman1966 3,610]

Spend $5 bux to replace the condenser.  When they get warm...after years and years.... this part fails.  Very Common.

 

[Joe Warren 75]

Wasn't the gas cap. Fuel runs freely. And I replaced the cap, just to be sure. 

 

Will replace condenser and report back. 

[Joe Warren 75]

Installed new condenser this morning. Tractor started right up and sounded good. Moved tractor 200', then let it  sit at a high idle for a minute while I was fetching some gloves. Same problem returned, tractor would loose rpm as if we're going to stall out, then catch its breath and rev up only to start to die again. So, tractor is acting up once engine warms up. Any ideas as to what is going on? 

[stevasaurus 22,229]

It sounds like it is not running long enough to heat up a coil, but a bad coil can do this.  If you have another horse swap the coils and see.  My experience...a bad coil takes about 20 minutes of running to warm up enough to do what you are having.